[llvm-commits] [llvm] r168652 - /llvm/trunk/docs/LangRef.html

Mon Nov 26 19:11:46 PST 2012

That's a good idea, I'll do that.

On Nov 26, 2012, at 6:05 PM, Sean Silva <silvas at purdue.edu> wrote:

> It seems needlessly repetitious end non-future-proof to copypaste the
> description of the flags for each instruction. Why don't you split
> them out into a section similar to how "Atomic Memory Ordering
> Constraints" <http://llvm.org/docs/LangRef.html#ordering> has been
> split out?
> 
> -- Sean Silva
> 
> On Mon, Nov 26, 2012 at 7:48 PM, Michael Ilseman <milseman at apple.com> wrote:
>> Author: milseman
>> Date: Mon Nov 26 18:48:29 2012
>> New Revision: 168652
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=168652&view=rev
>> Log:
>> Fast-math flags documentation added to LangRef
>> 
>> 
>> Modified:
>>    llvm/trunk/docs/LangRef.html
>> 
>> Modified: llvm/trunk/docs/LangRef.html
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.html?rev=168652&r1=168651&r2=168652&view=diff
>> ==============================================================================
>> --- llvm/trunk/docs/LangRef.html (original)
>> +++ llvm/trunk/docs/LangRef.html Mon Nov 26 18:48:29 2012
>> @@ -3970,7 +3970,7 @@
>> 
>> <h5>Syntax:</h5>
>> <pre>
>> -  <result> = fadd <ty> <op1>, <op2>   <i>; yields {ty}:result</i>
>> +  <result> = fadd [fast-math flags]* <ty> <op1>, <op2>   <i>; yields {ty}:result</i>
>> </pre>
>> 
>> <h5>Overview:</h5>
>> @@ -3982,7 +3982,28 @@
>>    floating point values. Both arguments must have identical types.</p>
>> 
>> <h5>Semantics:</h5>
>> -<p>The value produced is the floating point sum of the two operands.</p>
>> +<p>The value produced is the floating point sum of the two operands. This
>> +  instruction can also take any number of fast-math flags, which are
>> +  optimization hints to enable otherwise unsafe floating point
>> +  optimizations:</p>
>> +<ol>
>> +
>> +  <li><tt>nnan</tt>: No NaNs - Allow optimizations to assume the arguments and
>> +  result are not NaN. Such optimizations are required to retain defined behavior
>> +  over NaNs, but the value of the result is undefined.</li>
>> +
>> +  <li><tt>ninf</tt>: No Inf - Allow optimizations to assume the arguments and
>> +  result are not +/-Inf. Such optimizations are required to retain defined
>> +  behavior over +/-Inf, but the value of the result is undefined.</li>
>> +
>> +  <li><tt>nsz</tt>: No Signed Zeros: Allow optimizations to treat the
>> +  sign of a zero argument or result as insignificant. </li>
>> +
>> +  <li><tt>fast</tt>: Allow algebraically equivalent transformations that may
>> +  dramatically change results in floating point (e.g. reassociate). This flag
>> +  implies all the others.</li>
>> +
>> +</ol>
>> 
>> <h5>Example:</h5>
>> <pre>
>> @@ -4052,7 +4073,7 @@
>> 
>> <h5>Syntax:</h5>
>> <pre>
>> -  <result> = fsub <ty> <op1>, <op2>   <i>; yields {ty}:result</i>
>> +  <result> = fsub [fast-math flags]* <ty> <op1>, <op2>   <i>; yields {ty}:result</i>
>> </pre>
>> 
>> <h5>Overview:</h5>
>> @@ -4069,7 +4090,28 @@
>>    floating point values.  Both arguments must have identical types.</p>
>> 
>> <h5>Semantics:</h5>
>> -<p>The value produced is the floating point difference of the two operands.</p>
>> +<p>The value produced is the floating point difference of the two operands.  This
>> +  instruction can also take any number of fast-math flags, which are
>> +  optimization hints to enable otherwise unsafe floating point
>> +  optimizations:</p>
>> +<ol>
>> +
>> +  <li><tt>nnan</tt>: No NaNs - Allow optimizations to assume the arguments and
>> +  result are not NaN. Such optimizations are required to retain defined behavior
>> +  over NaNs, but the value of the result is undefined.</li>
>> +
>> +  <li><tt>ninf</tt>: No Inf - Allow optimizations to assume the arguments and
>> +  result are not +/-Inf. Such optimizations are required to retain defined
>> +  behavior over +/-Inf, but the value of the result is undefined.</li>
>> +
>> +  <li><tt>nsz</tt>: No Signed Zeros: Allow optimizations to treat the
>> +  sign of a zero argument or result as insignificant. </li>
>> +
>> +  <li><tt>fast</tt>: Allow algebraically equivalent transformations that may
>> +  dramatically change results in floating point (e.g. reassociate). This flag
>> +  implies all the others.</li>
>> +
>> +</ol>
>> 
>> <h5>Example:</h5>
>> <pre>
>> @@ -4138,7 +4180,7 @@
>> 
>> <h5>Syntax:</h5>
>> <pre>
>> -  <result> = fmul <ty> <op1>, <op2>   <i>; yields {ty}:result</i>
>> +  <result> = fmul [fast-math flags]* <ty> <op1>, <op2>   <i>; yields {ty}:result</i>
>> </pre>
>> 
>> <h5>Overview:</h5>
>> @@ -4150,7 +4192,28 @@
>>    floating point values.  Both arguments must have identical types.</p>
>> 
>> <h5>Semantics:</h5>
>> -<p>The value produced is the floating point product of the two operands.</p>
>> +<p>The value produced is the floating point product of the two operands.  This
>> +  instruction can also take any number of fast-math flags, which are
>> +  optimization hints to enable otherwise unsafe floating point
>> +  optimizations:</p>
>> +<ol>
>> +
>> +  <li><tt>nnan</tt>: No NaNs - Allow optimizations to assume the arguments and
>> +  result are not NaN. Such optimizations are required to retain defined behavior
>> +  over NaNs, but the value of the result is undefined.</li>
>> +
>> +  <li><tt>ninf</tt>: No Inf - Allow optimizations to assume the arguments and
>> +  result are not +/-Inf. Such optimizations are required to retain defined
>> +  behavior over +/-Inf, but the value of the result is undefined.</li>
>> +
>> +  <li><tt>nsz</tt>: No Signed Zeros: Allow optimizations to treat the
>> +  sign of a zero argument or result as insignificant. </li>
>> +
>> +  <li><tt>fast</tt>: Allow algebraically equivalent transformations that may
>> +  dramatically change results in floating point (e.g. reassociate). This flag
>> +  implies all the others.</li>
>> +
>> +</ol>
>> 
>> <h5>Example:</h5>
>> <pre>
>> @@ -4252,7 +4315,7 @@
>> 
>> <h5>Syntax:</h5>
>> <pre>
>> -  <result> = fdiv <ty> <op1>, <op2>   <i>; yields {ty}:result</i>
>> +  <result> = fdiv [fast-math flags]* <ty> <op1>, <op2>   <i>; yields {ty}:result</i>
>> </pre>
>> 
>> <h5>Overview:</h5>
>> @@ -4264,7 +4327,32 @@
>>    floating point values.  Both arguments must have identical types.</p>
>> 
>> <h5>Semantics:</h5>
>> -<p>The value produced is the floating point quotient of the two operands.</p>
>> +<p>The value produced is the floating point quotient of the two operands. This
>> +  instruction can also take any number of fast-math flags, which are
>> +  optimization hints to enable otherwise unsafe floating point
>> +  optimizations:</p>
>> +<ol>
>> +
>> +  <li><tt>nnan</tt>: No NaNs - Allow optimizations to assume the arguments and
>> +  result are not NaN. Such optimizations are required to retain defined behavior
>> +  over NaNs, but the value of the result is undefined.</li>
>> +
>> +  <li><tt>ninf</tt>: No Inf - Allow optimizations to assume the arguments and
>> +  result are not +/-Inf. Such optimizations are required to retain defined
>> +  behavior over +/-Inf, but the value of the result is undefined.</li>
>> +
>> +  <li><tt>nsz</tt>: No Signed Zeros: Allow optimizations to treat the
>> +  sign of a zero argument or result as insignificant. </li>
>> +
>> +  <li><tt>arcp</tt>: Allow Reciprocal: Allow optimizations to use the reciprocal
>> +  of an argument rather than perform division. </li>
>> +
>> +  <li><tt>fast</tt>: Allow algebraically equivalent transformations that may
>> +  dramatically change results in floating point (e.g. reassociate). This flag
>> +  implies all the others.</li>
>> +
>> +</ol>
>> +</p>
>> 
>> <h5>Example:</h5>
>> <pre>
>> @@ -4371,7 +4459,7 @@
>> 
>> <h5>Syntax:</h5>
>> <pre>
>> -  <result> = frem <ty> <op1>, <op2>   <i>; yields {ty}:result</i>
>> +  <result> = frem [fast-math flags]* <ty> <op1>, <op2>   <i>; yields {ty}:result</i>
>> </pre>
>> 
>> <h5>Overview:</h5>
>> @@ -4384,8 +4472,32 @@
>>    floating point values.  Both arguments must have identical types.</p>
>> 
>> <h5>Semantics:</h5>
>> -<p>This instruction returns the <i>remainder</i> of a division.  The remainder
>> -   has the same sign as the dividend.</p>
>> +  <p>This instruction returns the <i>remainder</i> of a division.  The remainder
>> +   has the same sign as the dividend.  This instruction can also take any number
>> +   of fast-math flags, which are optimization hints to enable otherwise unsafe
>> +   floating point optimizations:</p>
>> +
>> +<ol>
>> +
>> +  <li><tt>nnan</tt>: No NaNs - Allow optimizations to assume the arguments and
>> +  result are not NaN. Such optimizations are required to retain defined behavior
>> +  over NaNs, but the value of the result is undefined.</li>
>> +
>> +  <li><tt>ninf</tt>: No Inf - Allow optimizations to assume the arguments and
>> +  result are not +/-Inf. Such optimizations are required to retain defined
>> +  behavior over +/-Inf, but the value of the result is undefined.</li>
>> +
>> +  <li><tt>nsz</tt>: No Signed Zeros: Allow optimizations to treat the
>> +  sign of a zero argument or result as insignificant. </li>
>> +
>> +  <li><tt>arcp</tt>: Allow Reciprocal: Allow optimizations to use the reciprocal
>> +  of an argument rather than perform division. </li>
>> +
>> +  <li><tt>fast</tt>: Allow algebraically equivalent transformations that may
>> +  dramatically change results in floating point (e.g. reassociate). This flag
>> +  implies all the others.</li>
>> +
>> +</ol>
>> 
>> <h5>Example:</h5>
>> <pre>
>> 
>> 
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